


To Chase a Sin

by godtiermeme



Category: Fullmetal Alchemist: Brotherhood & Manga, Homestuck
Genre: Alternate Universe - Fusion, Canon-Typical Violence, F/F, Gen, M/M, Mainly a Homestuck fic, Post-Promised Day, Rose Lalonde and Dave Strider are Siblings
Language: English
Status: In-Progress
Published: 2019-07-10
Updated: 2019-07-10
Packaged: 2020-06-25 14:39:06
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 2,171
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19747771
Author URL: https://archiveofourown.org/users/godtiermeme/pseuds/godtiermeme
Summary: Half a century after the Promised Day, a familiar evil raises its head. An old enemy, reborn, as it was, as a harmless pawn, has eluded the public gaze for years. Now, it's back. A sort of miasma has settled over the thriving, nascent democracy of Amnestris, spreading a dark energy into the depths of tunnels long since forgotten. Pride has returned, awoken by forces unknown.Now, the fate of the world rests on the shoulders of four people: twin alchemists, the son of Ishvalan refugees, and a globetrotting seamstress. Backing them is a gang of old heroes and ragtag hooligans.What could possibly go wrong?(You probably don’t have to have extensive knowledge of Fullmetal Alchemist to enjoy this, but Homestuck knowledge is more mandatory.)





	To Chase a Sin

**Author's Note:**

> the chapter title is derived from the fullmetal alchemist: brotherhood song of the same name, [here's the chant version](https://www.youtube.com/watch?v=9gxjl1NSiSQ).

**Summary for the Chapter:**

> Welcome, dear readers, to the beginning of the end. Amnestris is in mortal danger, and the vast majority of its inhabitants haven't the slightest clue. It's amazing how short-sighted humans can be.

**Notes for the Chapter:**

> yes, that's a Doc Scratch & Selim Bradley tag, and i MADE IT with my own HANDS

**Somewhere on the banks of the Rain River**  
**Southern Amnestris**

A pair of twins stand side by side, watching as a toy boat floats down a lazily flowing river. One is male; the other, female. In appearances, they seem unrelated, but, through a series of strange coincidences, they share the same blood.

The woman has inherited more of her mother's Ishvalan genes. Her skin is a deep tan, and her eyes, a vivid red. A black headband holds back her mid-length white hair. Matching black lipstick stains her lips, and she pokes at the toy boat with a long stick. “I must say that when we advertised our services as alchemists, I did expect that we would, perhaps, more glamorous jobs than this. Fixing broken things, I understand. Not everyone can fix a radio, and it is exactly the sort of thing that your specialty caters to. Retrieving a child's toy boat, though?”

“I told you we'd just be stuck doing weird little errands, now, didn't I?” The man tuts. He rubs the back of his neck. Though his hair is also white, and his eyes the same shade of red (albeit hidden behind tinted lenses), his skin is pale, much like his father's. Paired arrays are tattooed on his palms, in blood-colored ink. When he claps his hands together, and the shapes overlap, he performs his particular brand of alchemy. The earth beneath him rearranges itself, forming into a sturdier, longer pole. It's made of a loose, soft bronze, but it does the trick. Pulling this rod up, the man reveals that, at the end, he has formed a hook. He leans out, latches onto the toy boat's sail, and begins pulling it in.

“You didn't come prepared today, Rose?” the man tuts. “Come on, sis, you've got to do better than that.”

The woman bristles at the jab. “Well, David, I'm sorry to break it to you, but cloth is a man-made commodity. Not much of it is simply strewn about, all willy-nilly, everywhere! Oh! Don't you wave that stupid boat in my face. Go, give it back to that snotty little child!” The alchemy circle embroidered on the sash around Rose's waist lights, and she mends the hole her brother had made in the sail's fabric. A tiny portion of the sash unravels, and fades into dust.

Now, it's the man's turn to tut. “Children are our damn future, Rose.” He walks a few yards away, to an eagerly waiting young girl, and hands her the recovered plaything. “There you go, kiddo. Good as new.” He ruffles the child's hair, and watches, pleased, as she skips away. Then, straightening his back, he turns his attentions back to his sister. He's about to say something, only to be interrupted.

“Did you remember to get our payment? Twelve hundred cens?” Rose's arms are folded across her chest, and her brows are furrowed. “My God, Dave, you absolute—!”

“Don't worry ‘bout it,” scoffs Dave. From the breast pocket of his red suit jacket, he pulls a wad of paper bills. As he continues speaking, he waves them in the air, “The mother paid me before we even started this stupid, roundabout, wild wooden ship chase. The cash is in the bag, and it ain't going—WAIT! NO! THE MONEY!” A stiff breeze whips by, pulling the cash from Dave's hand. It flits in the air, then dunks itself into the river.

Both of the siblings stand, dumbstruck, staring at the useless, soggy money.

“I am going to eviscerate you, David,” Rose says, her voice unnervingly calm.

“Not before I e-fuckin’-viscerate myself,” pouts Dave. He sits on the riverbank, tangling his fingers in his hair. “Well, sweet shit on a stick, that was the last of our cash.”

At this moment, in the depths of butter-fingered despair, the pair happens to be on the receiving end of another request. This time, a fisherman approaches from downstream. Like them, he carries Ishvalan blood, but he has no relationship to them. His hair is black and mussed, but his skin is dark, and his eyes are crimson. He's a slightly rotund man, with brows that seem to be stuck in a permanently furrowed state. “Someone said there were two high-and-mighty shit-for-brains alchemists running around town, claiming they'll fix anything for chump change,” he calls. He steps up, and drops a horribly mangled fishing rod on the ground. From his pocket, he takes a decent wad of cens. “I have about thirty-five-hundred for you. Fix my rod, and I'll stop telling people that I'd rather fuck a cow than deal with you two, with all your puffed-up somehow-alcohol-free carousing-type bullshit.”

Both Dave and Rose pause.

“I'm sorry, who're you?” Dave asks.

“Karkat Vantas.” The man jabs a thick, stubby thumb over his shoulder, in the direction of the nearby refugee shanty camp. “Some golden-haired douchebag blew through recently, and I'd left my rod on the street. Apparently, a car running over your rod isn't part of the fucking warranty, so I'm stuck.”

“You...” Rose pauses. Her voice is strained by the effort of keeping her giggles in check. “You do realize that was Prince Alphonse, right? Your fishing rod was unceremoniously pummeled by the wheels of the car of none other than Alphonse Elric.”

“I don't care who it is, dammit, I just want it fixed.” Karkat's voice is practically a growl, now. He shoves the cash forward, pressing it against Dave's chest. “Just fix my fishing pole, so I can go back to my mediocre life of idly casting a stick of metal into the river, pulling up marine life, and filleting it for other people's enjoyment.”

Dave grins. He begins to pocket the money, only for his sister to snatch it away from him. “Hey!”

“You're an imbecile, and I'm keeping this. It's not nearly enough to get us out of this town, though. It seems to me that we'll be staying another night at the inn.”

Dave rolls his eyes. He steps forward, claps his hands together, then places them on the rod. The remaining metal thins slightly, but the material shifts, rejoining and repairing itself. When it's complete, he stands up. “I can file the transmutation marks off for ya’, too. Just an extra eight-hundred-twenty cens! You're cute, too, so I'll discount you.”

“How about you kiss my ass, instead?” snarls Karkat, snatching up his rod. “Thank you for your menial labor. I hope I never see you again.”

At this exact moment, Rose stirs. A sound, akin to a loud ‘ah’, escapes her. She calls out to the receding figure of the grouchy fisherman. “WAIT! Karkat Vantas? You're from the Vantas family?”

Karkat pauses. He turns, shoulders his fishing rod, and cocks his head to the side. “Yeah. What's it mean to you?”

“Your father is famous for his Alkahestry studies, is he not?”

“Well, he's dead, now, so he _was_ famous. Don't mention it around here, you stupid shit. If you hadn't noticed, most hardcore Ishvalans aren't too happy about the whole defying God schtick,” counters Karkat.

Dave, by now, has wandered from his original position. Unnoticed by the fuming Vantas, he creeps up behind him. With interest, he notes the fine embroidery on the back of the other man's overcoat. “Shit, man, you're loaded. What're you doing in a place like this?”

Spinning on his heel, Karkat lands a solid punch to the gut of the gawking alchemist. “None of your fucking business, shit-for-brains. Look, you did what I wanted you to do. Will the two of you _please_ just leave me the fuck alone?” Another sizable stack of cash is produced from his pocket, held aloft between his middle and index fingers. “Motherfuckers, I'll pay you to just _leave me alone_.”

The money is gone before anything more can be said. Nonetheless, even as she pockets it, Rose persists, “Might you still be in possession of your father's research? I read some of his books, and I'm incredibly interested in seeing more.”

“In the name of Ishvala,” curses an increasingly frazzled Karkat, “I've given you money, what more do you want from me? If I let you into my house, and give you all of my father's research, will you promise to fuck off?”

Dave, thinking on his feet, comes up with a counter offer, “Let us stay overnight with you. It'll save us some money, and we'll be out of your weirdly and decidedly not-very-Ishvalan-of-you hair by the morning. Sound solid?”

“I'm seventy-five percent Ishvalan, you insensitive fuck. But, whatever. Fuck me! Fuck this planet! I'll show you to my place, and you can sleep on the floor for the night. After that, you better swear to whatever God you two pray to that you're gone before I'm awake.” Gesturing for them to follow, Karkat leads the pair away.

The trio travels down the winding river. The home they're looking for is near the riverbank, resting atop rotting wooden poles. The door is made of corrugated metal, and the interior is little more than a modest open-floor living area. Only the bathroom is separated by rickety interior walls. From beneath the bed, Karkat produces an armful of dusty leather-bound journals. He drops them in front of Rose.

“Happy fucking birthday,” he says.

True to form, Rose promptly skitters off, occupying herself with the notes.

Dave observes the most expensive thing in the room. “Nice radio, dude. An authentic Fuery model?”

“No, I nailed the Fuery faceplate to a radio I dredged from the bottom of the river. _Of course_ it's an authentic Fuery. I enjoy having some level of luxury in my life. Don't touch it.” Shoving Dave's hand away from the dial, Karkat turns it on. He tunes to the news station.

“Today's big news,” buzzes the announcer, “Is about the son of the late Führer Bradley. It is our unfortunate duty to report that Selim Bradley has gone missing! While he normally spends his days doing philanthropic work, he hasn't been seen for over a month! President Berthold Mustang has sworn the loyalty of the Amnestrian military to the search for our beloved Selim. Officials are also calling for participation from the public. Any willing members of the Alchemic Research Corps are invited to participate. The reward for Bradley's safe return has been set at ten million cens.”

“Oh, my,” chuckles the other radio personality. “The Mustang family is sparing no expense on this! That's quite an amount!”

The radio announcers continue to bicker, but all that sticks in Dave's head is the whopping amount. “Ten _million_ cens!?” Dave practically cheers. “Sweet tits, that's a lot. HEY, ROSE, DID YOU HEAR THAT!?”

“I did, dear brother. Please be more quiet. We'll join the search party tomorrow.”

“Oh, fuck yeah.” Dave smirks.

Karkat offers a critical snort of laughter. “And what makes _you_ , you fucking piss-drenched beanpole, think that you'll find Selim Bradley? What's your alchemy? Fixing fishing rods?”

Producing his symbolic pocket watch from his vest, Dave shakes his head. “I am the Metal Forging Alchemist,” he declares, “I create things from metal, and manipulate it.”

“You manipulate my patience, too,” huffs Karkat. ”Whatever. All of you stupid them-bos can run off and snap your own necks on impossible hunts for the missing, middle-aged son of some dead dictator. I'll just stay here, fish, and—”

The front door slams open. A tall woman, with dark brown skin and black hair, strides in. When she speaks, her voice is orotund and precise. “Karkat! Did you hear the recent announcement?”

“Did you hear about the concept of knocking on the door before you barge right on in, Kanaya!?”

Rose's attentions have snapped away from the book, and are now keenly (and gaily) trained upon the elegant newcomer. Her lips are pressed together, forming a line of intense, obvious attraction.

Unaware of the feelings of the other woman, and focused entirely on Karkat, Kanaya rolls her eyes. She puts her hands on her hips, and something about the pose radiates an aura of ‘perhaps it would be unwise to fuck with this particular woman’. “Well, I will certainly be joining the search party! Would you care to join me?”

A moan of pure exasperation breaks free from Karkat, rising from his chest, and bursting into the air as an eruption. “Fine! Whatever! Fuck this entire goddamned country! Ishvala abandoned all of you, because you're all absolute morons! There is a metric by which all people are measured, and, in every possible sense, everyone in Amnestris seems to somehow just roll up huge, glaring zeroes for the score. Maybe it's the air here. It turns you stupid. Fuck if I know. This entire affair is just, —” Karkat continues to drone on.

Coming out from her corner, timidly wringing her hands together, Rose approaches. She pauses her fidgeting, just long enough to extend her hand towards Kanaya. “Hello. My name is Rose Lalonde.”

“Ah. You look lovely,” Kanaya smiles, and Rose visibly melts. “Kanaya Maryam.”

The stage is set.

**Notes for the Chapter:**

> updates irregularly. i have only a vague idea where this is going, but i'm hoping it gets somewhere, because it's an idea i've been throwing around for a while. tags and characters will be added as we progress.

**Author's Note:**

> I'VE OPENED THE FINAL SEAL HOLDING BACK THE APOCALYPSE!


End file.
